[oilpan] Wrap NodeVector into CollectionRoot for ensure that contained nodes stay alive.

Source/core/dom/ContainerNode.h

Index: Source/core/dom/ContainerNode.h
diff --git a/Source/core/dom/ContainerNode.h b/Source/core/dom/ContainerNode.h
index 2f4c1e6db68ce007f09601fd12b55476b60e8caf..cc9cbacaef804decb300f12ba772f90cd2940cb3 100644
--- a/Source/core/dom/ContainerNode.h
+++ b/Source/core/dom/ContainerNode.h
@@ -272,14 +272,14 @@ inline bool Node::needsShadowTreeWalker() const
 // for a Node Vector that is used to store child Nodes of a given Node.
 // FIXME: Optimize the value.
 const int initialNodeVectorSize = 11;
-typedef Vector<Member<Node>, initialNodeVectorSize> NodeVector;
+typedef CollectionRoot<Vector<Member<Node>, initialNodeVectorSize> > NodeVector;
 
 inline void getChildNodes(Node* node, NodeVector& nodes)
 {
-    ASSERT(!nodes.size());
+    ASSERT(!nodes->size());
     for (Handle<Node> child = node->firstChild(); child; child = child->nextSibling()) {
         NoHandleScope scope;
-        nodes.append(child);
+        nodes->append(child);
     }
 }